In short: the Emailer will send an email for every feature passing through, to the address(es) specified.

Within your workspace you need to set up whatever testing/checking for that status and once you found that route one feature to the Emailer. It will send an email for every feature (so make sure you don't inadvertently build a spambot...) and you'll need credentials for an outgoing (SMTP or Gmail) mailserver of course.

Note: to use multiple email addresses, use the comma ( , ) to sepearate them, not the semicolon ( ; )